%0 Journal Article
%T Charge dynamics in molecular junctions: Nonequilibrium Green's Function approach made fast
%A S. Latini
%A E. Perfetto
%A A. -M. Uimonen
%A R. van Leeuwen
%A G. Stefanucci
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevB.89.075306
%X Real-time Green's function simulations of molecular junctions (open quantum systems) are typically performed by solving the Kadanoff-Baym equations (KBE). The KBE, however, impose a serious limitation on the maximum propagation time due to the large memory storage needed. In this work we propose a simplified Green's function approach based on the Generalized Kadanoff-Baym Ansatz (GKBA) to overcome the KBE limitation on time, significantly speed up the calculations, and yet stay close to the KBE results. This is achieved through a twofold advance: first we show how to make the GKBA work in open systems and then construct a suitable quasi-particle propagator that includes correlation effects in a diagrammatic fashion. We also provide evidence that our GKBA scheme, although already in good agreement with the KBE approach, can be further improved without increasing the computational cost.
%U http://arxiv.org/abs/1311.4691v1